Nozzles of the aforesaid type are widely used for texturing synthetic man-made yarn while the same is advanced at a high constant speed. The nozzles may and frequently do include stuffer boxes that receive the advancing yarn following passage thereof from the output end of the yarn duct within the nozzle. The sectional construction of the nozzle facilitates initial threading-up thereof. During each threading-up operation, the nozzle is "opened" by moving one of its sections away from the other of its sections. This permits convenient lateral insertion of the advancing yarn into the then separated yarn duct. Following insertion of the yarn into the duct, the normal abutting relationship between the nozzle sections is reestablished and retained during yarn-texturing operation of the nozzle.
Leakage of the hot air or other heated fluid from the yarn duct desirably should not occur during the yarn-texturing operation of the nozzle. However, in the prior-art nozzle constructions, significant leakage does occur at the juncture or interface between the abutting nozzle-section surfaces containing the yarn duct. The leakage will occur when there is significant unevenness of one or both of the aforesaid surfaces. Such leakage producing unevenness may be the result of improper finishing of the surfaces during manufacture of the nozzle sections. It may also result from warping of one or both of the surfaces, even when they were properly finished during manufacture, occurring when they are exposed to the heated fluid during operation of the nozzle.
Irrespective of its cause, leakage of the fluid from the nozzle during operation is highly undesirable, and a primary object of the present invention is elimination or at least minimization of the leakage problem.